The following table lists each of the three types, where you will find
them mounted, the pros and cons of each and a discussion about how you
might choose to use them.
| Type |
Locations
|
Pros |
Cons |
Notes |
| NFS |
/home/<username> |
| Global Namespace |
| Large file support(>2GB) |
| Backed up |
| Raid protection |
| Stable hardware |
| Accessible from compute nodes |
|
| Limited space |
| Cache difficulties (NFS) |
|
Your home directory is located on a filesystem that is NFS
mounted. This filesystem is located on a raid array and is served
by only one fileserver.
We recommend that you keep only small files such as scripts and binary files in your home
directory.
You might experience a time lag between when you change a file on
one node and when those changes will appear on another (it can
be up to 3 or 4 minutes). This is
an NFS problem and can not be fixed. You will need to work around it.
|
| PVFS |
/pvfs/<username> |
| Parallel writes to same file |
| TB filesystem |
| Large file support(>2GB) |
| Performance |
| Raid protection |
| No cache issues |
|
| Not accessible from service node |
| Problems with many small files |
| No support for hard links |
| Not backed up |
| Experimental filesystem |
|
PVFS is accessible from the compute nodes and should be
used for all large data writes and reads. It is not
accessible from the service node which means that
your executable cannot be in PVFS space and
your STDOUT and STDERR files cannot be in PVFS space
(i.e. your working directory at job start cannot be in
PVFS space).
|
| Local |
/tmp
/sandbox |
| Fast access |
| Large file support(>2GB) |
|
| Not accessible from service node |
| Not mounted remotely |
| GB filesystem |
| Not backed up |
| May be cleaned at anytime |
| No raid protection |
|
These filesystems are not available on the compute nodes
or on the service node.
This means you CANNOT put your executable in one of these
filesystems. It also means that your working directory
at the start of the job CANNOT be in one of these directories.
If you need a place to put temporary files that don't need to be
accessed by other nodes, we recommend that you put them into one
of these filesystems.
|